” Although solid-statetechnology overwhelmingly dominates today’s world of electronics, vacuum tubes are holding out in two small but vibrant areas. They do so for entirely different reasons. Microwave technology relies on tubes for their power-handling capability at high frequencies [“Tubes: still vital after all these years,” Robert S. Symons, IEEE Spectrum, April, 1998]. The other area–the creation and reproduction of music–is a more complicated and controversial story.Reference